Tank roof



E. W. WELP Jan. 8, 1935.

TANK ROOF Filed Dec. 7, 1932 fwefilir: Edward W Wfilp,

Patented Jan. 8, 1935 UNITED STATES TANK ROOF Edward W." Welp, Chicago,Ill., assignorto Graver Tank & Mfg. Com, East Chicago, Ind., acorporation of Illinois Application December 7, 1932, Serial No. 646,058

2 Claims. (Cl. 220-26) This invention relates to storage tanks, such asare used for storing oil or gasoline and more particularly to the roofsof such tanks. It has been illustrated as embodied in a floating roof.In the storage of gasoline and other volatile and combustible material,various problems arise. A fixed roof is unsatisfactory not only becauseof the costly structure necessary to make it self supporting when thetank is only partially full, but also because a large vapor space isleft abovethe gasoline, which of course is unsafe on account of thedanger of explosion. It is therefore, preferred to use a floating roofwhich, by its nature, eliminates the major portion of the gas space byresting on the oil.

With floating roofs however, there are the problems of sealing the edgesso far as possible without materially affecting the movement of theroof, and without permitting the formation of gas pockets of too large asize in connection with the seal, and of providing sealing means whichare not only cheap in construction, but thoroughly dependable in theiraction.

According to the present invention, these problems are solved byproviding on a floating roof of any type, a series of arcuate sealingplates shielded by a watershed, linked together and to the floating roofby flexible sealing strips to form a continuous cover and actuated bymeans such as a float which is wholly protected from the elements bysaid watershed and said roof.

With these and various other objects in view,

. the invention may consist of certain novel features of constructionand operation, as will be more fully described and particularly pointedout in the specification, drawing and claims appended hereto.

' In the drawing, which illustrates an embodiment of the device, andwherein like reference characters are used to designate like parts,

- Figure 1 is a fragmentary plan view of a tank; Figure 2 is a verticalcross-sectional view of the structure of Figure 1 built in accordancewith this invention; and

Figure 3 is a detail horizontal sectional view showing particularly theattachment of the outer sealing webs to the shoes, and is across-section taken through the line 3 -3 of Figure 2.

Although my invention may take many forms, only one has been chosen forillustration. In this form, the central portion of the roof illustratedin Figure 1 is commonplace and has been shown simply for the purpose ofillustration.

The roofmay comprise a main deck 10 which may include any desired framestructure and must of course include a bottom 12 and sides 14 which arefluid-tight to insure their permanently floating. As is the custom, sucha deck should also be drained in any suitable manner, as through aflexible or pivoted piping connection within the tank. There may be alsoa guide roller 16 mounted on the arm 18 secured to the deck and havingthe purpose of keeping the deck substantially centered within the tank20. .The arms 18 must of course be sufllciently short to permit freepassage of the deck up and down within the tank in spite of anyunevenness of the tank walls. All of the structure so far described isold in the art, merely forming the basis for the present invention, orcomprising an old element in inventive combinations; it therefore hasbeen shown very diagrammatically and described very briefly.

In order to close the space between the deck sides 14 and the walls ofthe tank 20,-or in other words to seal the liquid within the tank asnearly as possible, arcuate sealing plates 22 are provided, each ofwhich is secured to an arm 24 in any suitable manner, as by the rivetsillustrated. The arm 24 may be provided as at 26 with a bracket 28 whichmay be secured to the deck 10 in any suitable manner, as by welding.Secured to the inner end of the arm 24 preferably also by welding is afloat 30 which for cheapness of construction may comprise a simplecubical container vapor-tight on all of its sides except at its bottom32 which may be open. It will be readily understood that air or vapor isentrapped within the float 30, and since the float is always completelysubmerged, the buoyancy thereof is substantially uniform. This buoyancyis transmitted by the lever 24 to thrust the shoes 22 outwardly againstthe tank wall 20. The shoes 22 are curved in a horizontal plane to fitthe curvature of the tank walls, and are curved in a vertical planesufliciently to prevent their catching on outstanding rivets or jointsbetween plates or other obstructions. The outer surface may be providedwith a contact, plate 34 which preferably extends throughout thes'urface of the shoe 22, and if desired may-be made of some noncorrosivemetal, or may be coated or covered with a non-corrosive metal, such asbrass.

In order to seal the liquid between deck side 14 and shoes 22 from theatmosphere, a flexible sealing cover 36 and flexible sealing strips 38are provided. The flexible cover 36 may be secured to the shoes 22 by asecuring strip 40, riveted to said shoe to seal said cover thereto asshown. It may be secured to the deck side 14 in a similar manner bybeing clamped down between deck side Q 14 and members 42 which comprisea water-shed.

It is to be understood that the water-shed is preferably made up from anumber of segments joined together, although this detail has not beenshown. Sealing strips 38 may be secured to adjacent shoes in a similarmanner. Thus, as illustrated in Figure 3 they are clamped to the shoesby strips 44 which are riveted in place by rivets 46 which arepreferably providedflush heads at their outer ends. The contact plate 34may be perforated to receive these rivets, or to the extent thatassembly, conditions permit, may be attached to the outside of therivets. The operation of the structure hardly nee explanation. As thedeck is raised or lowered by the change in the level of the oil, theshoes 22 are likewise raised and lowered. In any given position the shoe22 is pressed by the buoyancy of the float against the tank wall 20.When the deck is raised or lowered, if the shoe should strike a rivet orother projection it would swing inwardly toward the deck side 14. Assoon as the projection is passed, the buoyancy of the float thrusts theshoe outwardly into its normal sealing position. The surface exposed forevaporation, it is evident with the structure shown, has

been reduced to a minimum, while the volume of the gas pocket is quitelow. The only surface exposed to the atmosphere would be that betweenthe shoes 22 and the wall 20. Inasmuch as all of the moving parts of theseal are protected from the weather, either by being submerged in theliquid or by being located below the watershed 42, the structure of thisinvention is unusually reliable.

It is to be understood that many other embodiments of the invention,including some in improved form, will be apparent, and in the course oftime more will be devised by those skilled in the art. It is not desiredthat this invention be limited to the details described, for its scopeincludes all such forms or improvements as come within the spirit of thefollowing claims, construed as broadly as the prior art will permit.

What is claimed is:

l. A floating roof for tanks including: a floating deck, a plurality oflevers pivoted to said deck, a sealing shoe connected to the outer endof each lever, means acting through said levers for urging said sealingshoes outwardly toward the wall of the tank, and rollers for limitingthe lateral movement of said deck; all the surfaces of said structurewhich contact with each other frictionally being located below thelowest normal level of liquid with respect to said root when said roofis floating, whereby said frictional parts are constantly lubricated bythe stored liquid.

2. A floating roof for tanks including: a floating deck, a plurality oflevers pivoted to said deck, a sealing shoe connected to the outer endof each lever, means acting through said levers for urging said sealingshoes outwardly toward the wall of the tank, and means for limiting thelateral movement of said deck; all the surfaces of said structure whichcontact with each other frictionally due to the inward and outwardmovement of said sealing shoes being located below the lowest normallevel of liquid with respect to said roof when said roof is floating,whereby said frictional parts are constantly lubricated by the storedliquid.

EDWARD W. WELP.

